The International Joint Conference on Artificial Intelligence (IJCAI) is the premier international gathering of leading AI researchers and practitioners from all over the world. Held biennially in odd-numbered years since 1969, IJCAI highlights the latest theoretical and applied results in all subfields of artificial intelligence. IJCAI-11, the twenty-second IJCAI conference, was held in Barcelona, Catalonia, Spain from July 16–22, 2011. This volume contains the papers presented, organized into ten major representative topics, namely agent-based and multiagent systems; constraints, satisfiability, and search; knowledge representation, reasoning, and logic; machine learning; multidisciplinary topics and applications; natural-language processing; planning and scheduling; robotics and vision; uncertainty in AI; and web and knowledge-based information systems. For 2011, the conference also included a special track on integrated and embedded AI, as well as a track of best papers from related conferences.